Silicone-based patient-side adhesive in a medical sensor

ABSTRACT

A patient monitoring sensor having a communication interface, through which the patient monitoring sensor can communicate with a monitor is provided. The patient monitoring sensor includes a light-emitting diode (LED) communicatively coupled to the communication interface and a detector, communicatively coupled to the communication interface, capable of detecting light. The patient monitoring sensor includes a silicone patient-side adhesive.

FIELD

The present disclosure relates generally to medical devices, and moreparticularly, to medical devices that monitor physiological parametersof a patient, such as pulse oximeters.

BACKGROUND

In the field of medicine, doctors often desire to monitor certainphysiological characteristics of their patients. Accordingly, a widevariety of devices have been developed for monitoring many suchphysiological characteristics. Such devices provide doctors and otherhealthcare personnel with the information they need to provide the bestpossible healthcare for their patients. As a result, such monitoringdevices have become an indispensable part of modern medicine.

One technique for monitoring certain physiological characteristics of apatient uses attenuation of light to determine physiologicalcharacteristics of a patient. This is used in pulse oximetry, and thedevices built based upon pulse oximetry techniques. Light attenuation isalso used for regional or cerebral oximetry. Oximetry may be used tomeasure various blood characteristics, such as the oxygen saturation ofhemoglobin in blood or tissue, the volume of individual blood pulsationssupplying the tissue, and/or the rate of blood pulsations correspondingto each heartbeat of a patient. The signals can lead to furtherphysiological measurements, such as respiration rate, glucose levels orblood pressure.

One issue in such sensors relates to the bandage of the sensor involvesremoval of the bandage and re-application. One example of this involvesmonitoring of a patient for blood oxygenation (e.g., SpO₂ or rSO₂),wherein the sensor (with particular emphasis on, for example, thedisposable part of the sensor that adheres to the patient) must beremoved to check the skin integrity. This can occur multiple times overa time span of a single sensor use, which can be up to 24 hours, 72hours, or more. Accordingly, the sensor must be removed and re-adheredwith minimal disruption to the patient, while still retaining sensoradherence to the skin.

Traditional pulse oximeter sensor designs utilize patient side adhesivessuch as acrylic or synthetic rubber adhesives. A common complaint withsuch sensors includes discomfort due to removal that is a frequenthospital procedure, or apparent discomfort expressed, for example byinfants in Neonatal Intensive Care Units (NICUs). Another commoncomplaint relates to loss of peel strength after the sensor removal,affecting its ability to be reapplied.

Minimal disruption to the skin is especially for patients with fragileskin, such as neonates. Disruption to the skin can occur over time asthe sensor is removed multiple times or during the first removal. Thesedisruptions can be as severe as skin tearing or just causing discomforton removal. In neonates, for example, any added stress, such asdisruption due to an adhesive bandage removal, can cause unwanteddesaturation events (where the blood oxygen levels decrease) and areavoided when possible.

Accordingly, there is a need in the art for more robust medical sensorsthat would provide more widespread acceptance in common usage, whichrequires removal and re-adherence of the sensor.

SUMMARY

The techniques of this disclosure generally relate to medical devicesthat monitor physiological parameters of a patient, such as pulseoximeters.

In one aspect, the present disclosure provides a patient monitoringsensor having a communication interface, through which the patientmonitoring sensor can communicate with a monitor. The patient monitoringsensor also includes a light-emitting diode (LED) communicativelycoupled to the communication interface and a detector, communicativelycoupled to the communication interface, capable of detecting light. Thepatient monitoring sensor further includes a patient-side adhesive withrepeatable removal and re-adherence characteristics, preventingdisruption to a patient while at the same time retaining sensoradherence to the skin, the patient-side adhesive comprising a siliconeadhesive.

In another aspect, the disclosure provides a patient monitoring sensorhaving a communication interface, through which the patient monitoringsensor can communicate with a monitor, wherein the sensor also includesa silicone patient-side adhesive that provides a peel force attachment,including after repositioning, for example in a range from about 0.5 to0.8 N/cm from skin. In exemplary embodiments, the adhesive retains 80%of the initial peel force from skin after the 18^(th) removal.

In further exemplary embodiments such patient-side adhesive does notdisrupt the skin (e.g., by removing only minimal skin protein) duringremoval, for example in a range from about 0.2 to 0.3 N/cm from skin. Inexemplary embodiments, adhesives in accordance with the presentdisclosure such minimal protein removal is at or below 1.5 microgramsper centimeter squared (μg/cm{circumflex over ( )}2). In other exemplaryembodiments protein removal is at or below 5 μg/cm{circumflex over( )}2, at or below 4 μg/cm{circumflex over ( )}2, at or below 3μg/cm{circumflex over ( )}2, at or below 2 μg/cm{circumflex over ( )}2or at or below 1 μg/cm{circumflex over ( )}2.

Further, such exemplary silicone patient-side adhesives do not increasewater loss through the skin (as measured via trans-epidermal water loss,per the below over a two hour period), for example by providing <1mg/cm{circumflex over ( )}2*hr increase from use. In other exemplaryembodiments, adhesives in accordance with the present disclosure providean increase of about 0.6 g/m{circumflex over ( )}2 h from baseline (theinitial measurement before the sensor is placed on the skin) fortransepidermal water loss (TEWL).

In exemplary embodiments, a suitable adhesive includes silicone gel orsilicone pressure sensitive adhesives with thickness between about 0.1mm to 1.5 mm.

In another aspect, the disclosure provides a patient monitoring system,having a patient monitor coupled to a patient monitoring sensor. Thepatient monitoring sensor includes a communication interface, throughwhich the patient monitoring sensor can communicate with the patientmonitor. The patient monitoring sensor also includes a light-emittingdiode (LED) communicatively coupled to the communication interface and adetector, communicatively coupled to the communication interface,capable of detecting light. The patient monitoring sensor furtherincludes a silicone patient-side adhesive.

The details of one or more aspects of the disclosure are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the techniques described in this disclosurewill be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a perspective view of an exemplary patient monitoringsystem including a patient monitor and a patient monitoring sensor, inaccordance with an embodiment;

FIG. 2 illustrates a perspective view of an exemplary patient monitoringsensor, in accordance with an embodiment;

FIG. 3 illustrates a schematic view of an exemplary patient monitoringsensor, in accordance with an embodiment;

FIG. 4 illustrates a layered schematic view of an exemplary patientmonitoring sensor bandage, in accordance with an embodiment; and

FIG. 5 illustrates a perspective view of an exemplary sensor assembly.

DETAILED DESCRIPTION

As has been noted above, traditional pulse oximeter sensor designsutilize patient side adhesives such as acrylic or synthetic rubberadhesives. A common complaint with such sensors includes discomfort dueto removal that is a frequent hospital procedure, or apparent discomfortexpressed, for example by infants in Neonatal Intensive Care Units(NICUs). Another common complaint relates to loss of peel strength afterthe sensor removal, affecting its ability to be reapplied.

The present disclosure recognizes that better adhesives for theseapplications may be identified, not only for comfort (gentleness), butalso for the well-being of patients in situations where bandages withadhesives must not only be worn, but must also be removed and reapplied.Further, consideration of adhesives must also account for a variety offactors, including without limitation: sweat from patients; humidity ofenvironments; contaminants on the patient-side of a sensor prior toplacement; amount(s) of dead skin sloughing; smoothness (morphology) ofepidermis; dwell time; variability in initial force provided by aclinician; part-to-part variation of the bandage footprint; materialstability; use case duration; and reapplication time interval(s).Additional factors include possible skin integrity or residue problemsupon removal.

Accordingly, the present disclosure describes a patient monitoringsensor that includes silicone patient-side adhesives provided as a partof the patient bandage, exemplary embodiments, the silicone patient-sideadhesive provides a peel force attachment, including afterrepositioning, for example in a range from about 0.5 to 0.8 N/cm fromskin. In exemplary embodiments, the adhesive retains at least 80% of theinitial peel force from skin after the 18^(th) removal. In furtherexemplary embodiments, the adhesive retains at least 60% of the initialpeel force from the skin after the 18^(th) removal. In further exemplaryembodiments, the adhesive retains at least 40% of the initial peel forcefrom the skin after the 18^(th) removal. In exemplary embodiments, peelforce is measured according to the ASTM D3330 standard.

In further exemplary embodiments such patient-side adhesive does notdisrupt the skin (e.g., by removing only minimal skin protein) duringremoval, for example in a range from about 0.2 to 0.3 N/cm from skin. Inexemplary embodiments, adhesives in accordance with the presentdisclosure such minimal protein removal is at or below 1.5 microgramsper centimeter squared (μm/cm{circumflex over ( )}2). In other exemplaryembodiments protein removal is at or below 5 μg/cm{circumflex over( )}2, at or below 4 μg/cm{circumflex over ( )}2, at or below 3μg/cm{circumflex over ( )}2, at or below 2 μg/cm{circumflex over ( )}2or at or below 1 μg/cm{circumflex over ( )}2.

Further, such exemplary silicone patient-side adhesives do not increasewater loss through the skin (as measured via trans-epidermal waterloss), for example by providing <1 mg/cm{circumflex over ( )}2*hrincrease from use. In other exemplary embodiments, adhesives inaccordance with the present disclosure provide an increase of about 0.6g/m{circumflex over ( )}2 h from baseline (the initial measurementbefore the sensor is placed on the skin) for transepidermal water loss(TEWL).

In exemplary embodiments, a suitable adhesive includes silicone gel orsilicone pressure sensitive adhesives with thickness between about 0.1mm to 1.5 mm.

In another aspect, the disclosure provides a patient monitoring sensorhaving a communication interface, through which the patient monitoringsensor can communicate with a monitor, wherein the sensor also includesa patient-side silicone adhesive providing comfort, including duringre-application, with minimal damage to the skin, as measured by thechange to the initial rate of water loss through the skin.

In another aspect, the disclosure provides a patient monitoring system,having a patient monitor coupled to a patient monitoring sensor. Thepatient monitoring sensor includes a communication interface, throughwhich the patient monitoring sensor can communicate with the patientmonitor. The patient monitoring sensor also includes a light-emittingdiode (LED) communicatively coupled to the communication interface and adetector capable of detecting light. The patient monitoring sensorincludes a patient-side silicone adhesive providing comfort, includingduring re-application, with minimal damage to the skin, as may bemeasured by the change to the initial rate of water loss through theskin.

Referring now to FIG. 1 , an embodiment of a patient monitoring system10 that includes a patient monitor 12 and a sensor 14, such as a pulseoximetry sensor, to monitor physiological parameters of a patient isshown. By way of example, the sensor 14 may be a NELLCOR™, or INVOS™sensor available from Medtronic (Boulder, Colo.), or another type ofoximetry sensor. Although the depicted embodiments relate to sensors foruse on a patient's fingertip, toe, or earlobe, it should be understoodthat, in certain embodiments, the features of the sensor 14 as providedherein may be incorporated into sensors for use on other tissuelocations, such as the forehead and/or temple, the heel, stomach, chest,back, or any other appropriate measurement site.

In the embodiment of FIG. 1 , the sensor 14 is a pulse oximetry sensorthat includes one or more emitters 16 and one or more detectors 18(plural detectors may be at different distances from the emitter(s)).For pulse oximetry applications, the emitter 16 transmits at least twowavelengths of light (e.g., red and/or infrared (IR)) into a tissue ofthe patient. For other applications, the emitter 16 may transmit 3, 4,or 5 or more wavelengths of light into the tissue of a patient. Thedetector 18 is a photodetector selected to receive light in the range ofwavelengths emitted from the emitter 16, after the light has passedthrough the tissue. Additionally, the emitter 16 and the detector 18 mayoperate in various modes (e.g., reflectance or transmission). In certainembodiments, the sensor 14 includes sensing components in addition to,or instead of, the emitter 16 and the detector 18. For example, in oneembodiment, the sensor 14 may include one or more actively poweredelectrodes (e.g., four electrodes) to obtain an electroencephalographysignal.

The sensor 14 also includes a sensor body 46 to house or carry thecomponents of the sensor 14. The body 46 includes a backing, or liner,provided around the emitter 16 and the detector 18, as well as anadhesive layer (not shown in FIG. 1 ) on the patient side. The sensor 14may be reusable (such as a durable plastic clip sensor), disposable(such as an adhesive sensor including a bandage/liner), or partiallyreusable and partially disposable.

In the embodiment shown, the sensor 14 is communicatively coupled to thepatient monitor 12. In certain embodiments, the sensor 14 may include awireless module configured to establish a wireless communication 15 withthe patient monitor 12 using any suitable wireless standard. Forexample, the sensor 14 may include a transceiver that enables wirelesssignals to be transmitted to and received from an external device (e.g.,the patient monitor 12, a charging device, etc.). The transceiver mayestablish wireless communication 15 with a transceiver of the patientmonitor 12 using any suitable protocol. For example, the transceiver maybe configured to transmit signals using one or more of the ZigBeestandard, 802.15.4x standards WirelessHART standard, Bluetooth standard,IEEE 802.11x standards, or MiWi standard. Additionally, the transceivermay transmit a raw digitized detector signal, a processed digitizeddetector signal, and/or a calculated physiological parameter, as well asany data that may be stored in the sensor, such as data relating towavelengths of the emitters 16, or data relating to input specificationfor the emitters 16, as discussed below. Additionally, or alternatively,the emitters 16 and detectors 18 of the sensor 14 may be coupled to thepatient monitor 12 via a cable 24 through a plug 26 (e.g., a connectorhaving one or more conductors) coupled to a sensor port 29 of themonitor. In certain embodiments, the sensor 14 is configured to operatein both a wireless mode and a wired mode. Accordingly, in certainembodiments, the cable 24 is removably attached to the sensor 14 suchthat the sensor 14 can be detached from the cable to increase thepatient's range of motion while wearing the sensor 14.

The patient monitor 12 is configured to calculate physiologicalparameters of the patient relating to the physiological signal receivedfrom the sensor 14. For example, the patient monitor 12 may include aprocessor configured to calculate the patient's arterial blood oxygensaturation, tissue oxygen saturation, pulse rate, respiration rate,blood pressure, blood pressure characteristic measure, autoregulationstatus, brain activity, and/or any other suitable physiologicalcharacteristics. Additionally, the patient monitor 12 may include amonitor display 30 configured to display information regarding thephysiological parameters, information about the system (e.g.,instructions for disinfecting and/or charging the sensor 14), and/oralarm indications. The patient monitor 12 may include various inputcomponents 32, such as knobs, switches, keys and keypads, buttons, etc.,to provide for operation and configuration of the patient monitor 12.The patient monitor 12 may also display information related to alarms,monitor settings, and/or signal quality via one or more indicator lightsand/or one or more speakers or audible indicators. The patient monitor12 may also include an upgrade slot 28, in which additional modules canbe inserted so that the patient monitor 12 can measure and displayadditional physiological parameters.

Because the sensor 14 may be configured to operate in a wireless modeand, in certain embodiments, may not receive power from the patientmonitor 12 while operating in the wireless mode, the sensor 14 mayinclude a battery to provide power to the components of the sensor 14(e.g., the emitter 16 and the detector 18). In certain embodiments, thebattery may be a rechargeable battery such as, for example, a lithiumion, lithium polymer, nickel-metal hydride, or nickel-cadmium battery.However, any suitable power source may be utilized, such as, one or morecapacitors and/or an energy harvesting power supply (e.g., a motiongenerated energy harvesting device, thermoelectric generated energyharvesting device, or similar devices).

As noted above, in an embodiment, the patient monitor 12 is a pulseoximetry monitor and the sensor 14 is a pulse oximetry sensor. Thesensor 14 may be placed at a site on a patient with pulsatile arterialflow, typically a fingertip, toe, forehead or earlobe, or in the case ofa neonate, across a foot. Additional suitable sensor locations include,without limitation, the neck to monitor carotid artery pulsatile flow,the wrist to monitor radial artery pulsatile flow, the inside of apatient's thigh to monitor femoral artery pulsatile flow, the ankle tomonitor tibial artery pulsatile flow, and around or in front of the ear.The patient monitoring system 10 may include sensors 14 at multiplelocations. The emitter 16 emits light which passes through the bloodperfused tissue, and the detector 18 photoelectrically senses the amountof light reflected or transmitted by the tissue. The patient monitoringsystem 10 measures the intensity of light that is received at thedetector 18 as a function of time.

A signal representing light intensity versus time or a mathematicalmanipulation of this signal (e.g., a scaled version thereof, a log takenthereof, a scaled version of a log taken thereof, etc.) may be referredto as the photoplethysmograph (PPG) signal. In addition, the term “PPGsignal,” as used herein, may also refer to an absorption signal (i.e.,representing the amount of light absorbed by the tissue) or any suitablemathematical manipulation thereof. The amount of light detected orabsorbed may then be used to calculate any of a number of physiologicalparameters, including oxygen saturation (the saturation of oxygen inpulsatile blood, SpO2), an amount of a blood constituent (e.g.,oxyhemoglobin), as well as a physiological rate (e.g., pulse rate orrespiration rate) and when each individual pulse or breath occurs. ForSpO2, red and infrared (IR) wavelengths may be used because it has beenobserved that highly oxygenated blood will absorb relatively less Redlight and more IR light than blood with a lower oxygen saturation. Bycomparing the intensities of two wavelengths at different points in thepulse cycle, it is possible to estimate the blood oxygen saturation ofhemoglobin in arterial blood, such as from empirical data that may beindexed by values of a ratio, a lookup table, and/or from curve fittingand/or other interpolative techniques.

Referring now to FIG. 2 , an embodiment of a patient monitoring sensor100 in accordance with an embodiment is shown. As may be seen, the shapeor profile of various components may vary. The sensor 100 includes abody 102 that includes a flexible circuit. The sensor 100 includes anLED 104 and a detector 106 disposed on the body 102 of the sensor 100.

While any number of exemplary sensor designs are contemplated herein, inthe illustrated exemplary embodiment, the body 100 includes a flapportion 116 that includes an aperture 108. The flap portion 116 isconfigured to be folded at a hinge portion 114 such that the aperture108 overlaps the detector 106. In one embodiment, the flap portion 116includes an adhesive 110 that is used to secure the flap portion 116 tothe body 102 after the flap portion 116 is folded at the hinge portion114.

The sensor 100 includes a plug 120 that is configured to be connected toa patient monitoring system, such as the one shown in FIG. 1 . Thesensor 100 also includes a cable 122 that connects the plug 120 to thebody 102 of the sensor 100. The cable 122 includes a plurality of wires124 that connect various parts of the plug 120 to terminals 126 disposedon the body 102. The flexible circuit is disposed in the body 102 andconnects the terminals 126 to the LED 104 and the detector 106. Inaddition, one of the terminals 126 connect a ground wire to the flexiblecircuit.

In exemplary embodiments, the aperture 108 is configured to provideelectrical shielding to the detector 106. In exemplary embodiments,aperture 108 also limits the amount of light that is received by thedetector 106 to prevent saturation of the detector. In exemplaryembodiments, the configuration of the aperture 108, i.e., a number,shape, and size of the openings that define the aperture 108 can vary.As illustrated, in one embodiment, the aperture 108 includes a singleround opening. In other embodiments, the aperture 108 can include one ormore openings that have various shapes and sizes. The configuration ofthe aperture 108 is selected to provide electrical shielding for thedetector 106 and/or control the amount of light that is received by thedetector 106. In exemplary embodiments, the body 102 includes a visualindicator 112 that is used to assure proper alignment of the flapportion 116 when folded at the hinge portion 114.

Referring now to FIG. 3 , a patient monitoring sensor 200 in accordancewith an embodiment is shown. In exemplary embodiments, a faraday cage240 is formed around the detector 206 by folding the flap portion 116over a portion of the body 102 of the sensor 200.

As we have noted, regardless of sensor configuration particulars of theabove-described exemplary embodiments, the sensor includes a siliconepatient-side adhesive. Exemplary benefits of such a siliconepatient-side adhesive include a peel force attachment, including afterrepositioning, minimization of disruption of and damage to the skin(e.g., by removing only minimal skin protein) during removal andcomfort, among others.

Further, in embodiments where at least a portion of the materials usedin the construction of the sensor comprise hydrophobic materials, forexample including a polyester backing, such silicone patient-sideadhesives contribute to hydrophobic qualities of the bandage, preventingadverse odor and a reduction of bacteria over time of use. Accordingly,such a sensor, including the silicone patient-side adhesive, will absorbless moisture from the environment, for example from a humid environmentor from handwashing, etc. This provides a sensor with more longevity ofuse and more pleasing effects, and further results in reduction of totalcost per patient by extending the useful life of the sensor.

FIG. 4 illustrates an expanded perspective view generally at 300 of anexemplary layered body/bandage configuration for a pulse oximetersensor. The configuration includes: an upper bandage 350; an exemplarybottom tape/patient adhesive 352; exemplary top internal liner 354 andbottom internal liner 356, which in exemplary embodiments are discardedduring sensor assembly, allowing the bandage to open like a leaflet toinsert the flex circuit of FIGS. 2 and 3 into the bandage; a top lightblocking layer, for example a metallized tape; a bottom light blockinglayer 360, for example a metallized tape with holes 362 configured toallow light to shine through; and a disc 364, comprising for example apolyethylene material, configured to reduce pressure from the LED on thepatient. In exemplary embodiments, bottom tape 352 comprises an adhesivelayer with a release liner 366 on the patient facing side of tape 352.

FIG. 5 illustrates a perspective view of exemplary assembly of the flexcircuit 200 of FIGS. 2 and 3 into the bandage 300, with internal liners354, 356 removed to allow positioning of the flex circuit 200 into thebandage, between the light blocking layers 358, 360. As is shown,detector 106 is positioned over hole 362. LED 104 is positioned overdisc or ring 364 (which is positioned over another hole 362 (not shownin FIG. 5 )). Rapid assembly is facilitated by removable liners 354,356, as well as the upper bandage 350 and light blocking layer 358acting as a foldable leaflet 402, the exemplary bandage constructionprovided as a sub-assembly configured to provide high-volume, fast andrepeatable production of sensor assemblies.

Exemplary materials for backing material includes plastics, such aspolypropylene (PP), polyester (PES), polyethylene (PE), urethanes,silicone, or the like. Additionally, various layers of the device may beconstructed of one or more hydrophobic materials.

Exemplary materials for patient adhesive include gentle removaladhesives, such as various silicone adhesives that provide resilience(for re-adhesion) after repositioning, comfort, lack of water lossthrough patient skin (as measured via trans-epidermal water loss), whichlack of water loss correlates with gentle release of the adhesive, etc.

One or more specific embodiments of the present techniques will bedescribed below. In an effort to provide a concise description of theseembodiments, not all features of an actual implementation are describedin the specification. It should be appreciated that in the developmentof any such actual implementation, numerous implementation-specificdecisions must be made, which may vary from one implementation toanother.

It should be understood that various aspects disclosed herein may becombined in different combinations than the combinations specificallypresented in the description and accompanying drawings. It should alsobe understood that, depending on the example, certain acts or events ofany of the processes or methods described herein may be performed in adifferent sequence, may be added, merged, or left out altogether (e.g.,all described acts or events may not be necessary to carry out thetechniques). In addition, while certain aspects of this disclosure aredescribed as being performed by a single module or unit for purposes ofclarity, it should be understood that the techniques of this disclosuremay be performed by a combination of units or modules associated with,for example, a medical device.

What is claimed is:
 1. A patient monitoring sensor, comprising acommunication interface, through which the patient monitoring sensor cancommunicate with a monitor; a light-emitting diode (LED) communicativelycoupled to the communication interface; a detector, communicativelycoupled to the communication interface, capable of detecting light; abandage provided around the light-emitting, diode and the detector; anda silicone patient-side adhesive provided on the bandage, wherein thesilicone patient-side adhesive has a peel force of between about 0.5 to0.8 N/cm from skin, including after at least one repositioning.
 2. Thepatient monitoring sensor of claim 1, wherein the silicone patient-sideadhesive also comprises a release liner.
 3. Tice patient monitoringsensor of claim 1, wherein the silicone patient-side adhesive retains atleast 80% of the initial peel force from skin after the 18^(th) removal.4. The patient monitoring sensor of claim 1, wherein the siliconepatient-side adhesive retains at least 60% of the initial peel forcefrom skin after the 18^(th) removal.
 5. The patient monitoring sensor ofclaim 1, wherein the silicone patient-side adhesive is characterized byremoval of skin protein of less than 5 μg/cm{circumflex over ( )}2. 6.The patient monitoring sensor of claim 1; wherein the siliconepatient-side adhesive is characterized by removal of skin protein ofless than 3 μg/cm{circumflex over ( )}2.
 7. The patient monitoringsensor of claim 1, wherein the silicone patient-side adhesive ischaracterized by removal of skin protein of less than about 1.5μg/cm{circumflex over ( )}2.
 8. The pad ent monitoring sensor of claim1, wherein the silicone patient-side adhesive is characterized by waterloss through the skin of less than <1 mg/cm{circumflex over ( )}2*hrfrom baseline.
 9. The patient monitoring sensor of claim 1, wherein thesilicone patient-side adhesive has a thickness between 0.1 mm and 1.5mm.
 10. A method for making a patient monitoring system, comprising:providing a communication interface; through which the patientmonitoring sensor can communicate with a monitor; coupling alight-emitting diode (LED) communicatively to the communicationinterface; coupling a detector capable of detecting lightcommunicatively to the communication interface; positioning a bandageprovided around the light-emitting diode and the detector; and aproviding a silicone patient-side adhesive on the bandage, wherein thesilicone patient-side adhesive has a peel force of between about 0.5 to0.8 N/cm from skin, including after at least one repositioning.
 11. Themethod of claim 10, wherein the silicone patient-side adhesive retainsat least 80% of the initial peel force from skin after the 18^(th)removal.
 12. The method of claim 10, wherein the silicone patient-sideadhesive retains at least 60% of the initial peel force from skin afterthe 18^(th) removal.
 13. The method of claim 10, wherein the siliconepatient-side adhesive retains at least 40% of the initial peel forcefrom skin after the 18^(th) removal.
 14. The method of claim 10, whereinthe silicone patient-side adhesive is characterized by removal of skinprotein of less than 5 μg/cm{circumflex over ( )}2.
 15. The method ofclaim 10, wherein the silicone patient-side adhesive is characterized byremoval of skin protein of less than 3 μg/cm{circumflex over ( )}2. 16.The method of claim 10, wherein the silicone patient-side adhesive ischaracterized by removal of skin protein of less than about 1.5μg/cm{circumflex over ( )}2.
 17. The method of claim 10, wherein thesilicone patient-side adhesive is characterized by water loss throughthe skin of less than <1 mg/cm{circumflex over ( )}2*hr from baseline.18. The method of claim 10, wherein the silicone patient-side adhesivehas a thickness between 0.1 mm and 1.5 mm.